Move go generate comment

Author: owen-mc

go/ql/test/library-tests/semmle/go/dataflow/flowsources/local/database/test_mongo_driver_mongo.go

@@ -1,6 +1,7 @@
-//go:generate depstubber -vendor go.mongodb.org/mongo-driver/mongo Client,Collection,Database
 package test
 
+//go:generate depstubber -vendor go.mongodb.org/mongo-driver/mongo Client,Collection,Database
+
 import (
 	"context"